{
  "title": "MCP Protocol Relationships vs Network Connections",
  "schemaVersion": "1.0",
  "researchFreeze": "2026-08-26",
  "protocolRevision": "2026-07-28",
  "count": 15,
  "records": [
    {
      "recordId": "R5-REL01",
      "concept": "Host product",
      "definition": "User-facing application or agent environment coordinating models, permissions and clients",
      "example": "VS Code, Claude Desktop, ChatGPT",
      "notEquivalentTo": "A single MCP client connection",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL02",
      "concept": "MCP client",
      "definition": "Protocol component created by a host for one logical server relationship",
      "example": "The VS Code client instance for a GitHub server",
      "notEquivalentTo": "The entire editor or AI product",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL03",
      "concept": "MCP server",
      "definition": "Server-side protocol implementation exposing capabilities",
      "example": "A GitHub, filesystem or database server",
      "notEquivalentTo": "The model or host",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL04",
      "concept": "Logical client–server relationship",
      "definition": "Protocol association between one client component and one server",
      "example": "Client A using Server A's tools",
      "notEquivalentTo": "One TCP connection or one persistent session",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL05",
      "concept": "HTTP request",
      "definition": "One transport exchange in current Streamable HTTP",
      "example": "POST carrying tools/list",
      "notEquivalentTo": "An MCP session",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL06",
      "concept": "TCP/TLS connection",
      "definition": "Network transport connection managed by HTTP stack",
      "example": "Reused HTTP/2 or HTTP/3 connection",
      "notEquivalentTo": "MCP client identity",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL07",
      "concept": "Legacy protocol session",
      "definition": "State established by initialize and optionally identified by Mcp-Session-Id",
      "example": "2025 Streamable HTTP session",
      "notEquivalentTo": "Current MCP core behavior",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL08",
      "concept": "stdio stream",
      "definition": "Bidirectional newline-delimited JSON-RPC over child process stdin/stdout",
      "example": "Local filesystem server",
      "notEquivalentTo": "A network session or remote endpoint",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL09",
      "concept": "Server endpoint",
      "definition": "URL or process address exposing a logical server",
      "example": "https://service.example/mcp",
      "notEquivalentTo": "One server process",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL10",
      "concept": "Server replica",
      "definition": "One horizontally scaled implementation instance",
      "example": "Container behind a load balancer",
      "notEquivalentTo": "A separate logical server identity",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL11",
      "concept": "Server package",
      "definition": "Distributed software artifact implementing a server",
      "example": "npm or Python package",
      "notEquivalentTo": "A running server or approved service",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL12",
      "concept": "Server configuration",
      "definition": "Host-specific instructions for locating/starting a server",
      "example": "mcpServers JSON entry",
      "notEquivalentTo": "Protocol specification",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL13",
      "concept": "SDK",
      "definition": "Library used to implement client or server roles",
      "example": "Official TypeScript SDK",
      "notEquivalentTo": "A host, client connection or server until instantiated",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL14",
      "concept": "Model tool call",
      "definition": "Structured request produced by a model/provider tool system",
      "example": "create_issue arguments",
      "notEquivalentTo": "MCP tools/call, though hosts may map between them",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    },
    {
      "recordId": "R5-REL15",
      "concept": "Agent loop",
      "definition": "Application logic coordinating model calls, tool use, results and termination",
      "example": "Coding-agent harness",
      "notEquivalentTo": "MCP server",
      "packageSourceIds": [
        "S001",
        "S005"
      ],
      "sourceIds": [
        "S121",
        "S057"
      ]
    }
  ]
}